On FX's smart Rescue Me, fire fighters are human too--not that they would ever want it spread around

Denis Leary is not a guy you associate with putting out fires. He lights them--the small, contained blazes at the end of the cigarettes he chain-smoked through his angry, comic diatribes, like the one-man show No Cure for Cancer. Yet here he is, backstage at the set of his new TV series, in a New York City fire-department (F.D.N.Y.) uniform, picking at a plate of chicken with rice and beans, talking earnestly about his cousin Jeremiah Lucey, a real-life fireman in Worcester, Mass.

One night in 1999, Leary says, Lucey "was filling in for another guy as a favor. He...